Method for producing vapor deposition mask, and method for producing organic semiconductor element

ABSTRACT

A method for producing a vapor deposition mask capable of satisfying both enhancement in definition and reduction in weight even when a size is increased, and a method for producing an organic semiconductor element capable of producing an organic semiconductor element with high definition are provided. A vapor deposition mask is produced by the steps of preparing a metal plate with a resin layer in which a resin layer is provided on one surface of a metal plate, forming a metal mask with a resin layer by forming a slit that penetrates through only the metal plate, for the metal plate in the metal plate with a resin layer, and thereafter, forming a resin mask by forming openings corresponding to a pattern to be produced by vapor deposition in a plurality of rows lengthwise and crosswise in the resin layer by emitting a laser from the metal mask side.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.15/455,409, filed Mar. 10, 2017, which is a continuation of U.S.application Ser. No. 15/158,951, filed May 19, 2016, now abandoned,which is a continuation of U.S. application Ser. No. 14/923,497, filedOct. 27, 2015, now U.S. Pat. No. 9,379,324, issued Jun. 28, 2016, whichis a division of U.S. application Ser. No. 14/370,875, filed Jul. 7,2014, now U.S. Pat. No. 9,203,028, issued Dec. 1, 2015, which in turn isthe National Stage of International Application No. PCT/JP2013/050423,filed Jan. 11, 2013, which designated the United States, the entiretiesof which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a method for producing a vapordeposition mask, and a method for producing an organic semiconductorelement.

BACKGROUND OF THE INVENTION

Conventionally, in production of an organic EL element, a vapordeposition mask that is composed of a metal formed by a number ofmicroscopic slits being arranged in parallel with one another atmicroscopic spaces in a region that should be subjected to vapordeposition, for example, has been used in formation of an organic layerof an organic EL element or a cathode electrode. While in the case ofusing the vapor deposition mask, the vapor deposition mask is placed ona substrate front surface that should be subjected to vapor depositionand is held by using a magnet from a back surface, the rigidity of theslits is extremely small, and therefore, distortion easily occurs to theslits when the vapor deposition mask is held on the substrate frontsurface, which becomes an obstacle to enhancement in definition orupsizing of the products in which the slit lengths are large.

Various studies have been made on the vapor deposition masks forpreventing distortion of slits, and, for example, Patent Literature 1proposes a vapor deposition mask including a base plate that also servesa first metal mask including a plurality of openings, a second metalmask including a number of microscopic slits in regions to cover theaforementioned openings, and a mask pulling and holding device thatpositions the second metal mask on the base plate in a state in whichthe second metal mask is pulled in the longitudinal direction of theslits. Namely, the vapor deposition mask with two kinds of metal masksbeing combined is proposed. It is indicated that according to the vapordeposition mask, slit precision can be ensured without occurrence ofdistortion to the slits.

Incidentally, in recent years, with upsizing of the products usingorganic EL elements or increase in substrate sizes, a demand forupsizing are also growing with respect to vapor deposition masks, andthe metal plates for use in production of the vapor deposition maskscomposed of metals are also upsized. However, with the present metalprocessing technique, it is difficult to form slits in a large metalplate with high precision, and even if distortion in slit portions canbe prevented by the method proposed in the above described PatentLiterature 1 or the like, the method or the like cannot respond toenhancement in definition of the slits. Further, in the case of use of avapor deposition mask composed of only a metal, the mass thereof alsoincreases with upsizing, and the total mass including a frame alsoincreases, which becomes a hindrance to handling.

CITATION LIST

-   Patent Literature 1: Japanese Patent Laid-Open No. 2003-332057

SUMMARY OF THE INVENTION

The present invention is made in the light of the situation as above,and has main problems of providing a method for producing a vapordeposition mask that can satisfy both enhancement in definition andreduction in weight even when a size is increased, and of providing amethod for producing an organic semiconductor element that can producethe organic semiconductor element with high precision.

The present invention for solving the above described problem is amethod for producing a vapor deposition mask that is formed by a metalmask provided with a slit, and a resin mask that is positioned on afront surface of the metal mask, and has openings corresponding to apattern to be produced by vapor deposition arranged by lengthwise andcrosswise in a plurality of rows being stacked on each other, andincludes the steps of preparing a metal plate with a resin layer inwhich a resin layer is provided on one surface of the metal plate,forming a metal mask with a resin layer by forming a slit thatpenetrates through only the metal plate, for the metal plate in themetal plate with a resin layer, and therefore, forming a resin mask byforming the openings corresponding to a pattern to be produced by vapordeposition in a plurality of rows lengthwise and crosswise in the resinlayer by emitting a laser from the metal mask side.

In the above described invention, the step of forming the metal maskwith a resin layer is a step of forming a resist pattern by coating asurface where a resin layer is not provided, of the metal plate with aresin layer with a resist material, masking the resist material with useof a mask in which a slit pattern is formed, and forming a resistpattern to performing exposure and development, subjecting the metalplate to etching processing with use of the resist pattern as an etchingresistant mask, and cleaning and removing the resist pattern afteretching is finished.

Further, on the other hand, in the invention described above, the resistpattern may be allowed to remain as it is without being cleaned andremoved.

Further, after the step of forming the metal mask with a resin layer,the step of fixing the metal mask with a resin layer onto a framecontaining a metal is further included, and after the metal mask with aresin layer is fixed to the frame, the step of forming the resin maskmay be performed.

Further, the present invention for solving the above described problemis a method for producing an organic semiconductor element, wherein thevapor deposition mask that is produced according to the productionmethod having the above described features is used.

According to the method for producing a vapor deposition mask of thepresent invention, the vapor deposition mask capable of satisfying bothenhancement in definition and reduction in weight even when a size isincreased can be produced with high yield. Further, according to themethod for producing an organic semiconductor element of the presentinvention, an organic semiconductor element can be produced with highprecision.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 (a)-(e) are a process chart for describing a first productionmethod of the vapor deposition mask of the present invention;

FIGS. 2 (a)-(e) are a process chart for describing a second method forproducing the vapor deposition mask of the present invention;

FIG. 3 (a) is a front view of the vapor deposition mask that is producedaccording to the first production method, seen from a metal mask side,and FIG. 3 (b) is an enlarged sectional view of a vapor deposition mask100 that is produced according to the first production method;

FIG. 4 is an enlarged sectional view of the vapor deposition mask thatis produced according to the second production method;

FIGS. 5 (a) and (b) are front views of the vapor deposition mask that isproduced according to the production method of the present invention,seen from a metal mask side;

FIGS. 6 (a)-(c) are schematic sectional views showing a relation of ashadow and a thickness of the metal mask;

FIGS. 7 (a)-(d) are partial schematic sectional views showing a relationof a slit of the metal mask, and an opening of a resin mask; and

FIG. 8 is a partial schematic sectional view showing a relation of theslit of the metal mask and the opening of the resin mask.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, a method for producing a vapor deposition mask of thepresent invention will be specifically described with use of thedrawings. Note that in the following explanation, process steps will bemainly described first, and description of a material and the like willbe made together when the vapor deposition mask that is producedaccording to the production method is described.

First Production Method

FIGS. 1 (a)-(e) are a process chart for describing a first productionmethod of the vapor deposition mask of the present invention. Note thatFIGS. 1 (a) to (e) are all sectional views.

As shown in FIG. 1 (a), a metal plate 60 with a resin layer in which aresin layer 67 is provided on one surface of the metal plate 61 isprepared. Here, a method for preparing the metal plate 60 with a resinlayer is not specially limited, and the metal plate 60 with a resinlayer that is commercially available may be purchased, or the metalplate 60 with a resin layer may be made by providing a resin layer on afront surface of the metal plate. As a method for providing the resinlayer on the front surface of the metal plate, the metal plate is coatedwith a coating solution containing a resin to be a resin layer, and isdried, whereby the metal plate 60 with a resin layer can be obtained. Inplace of the method, a metal plate with a resin layer also can beobtained by bonding a resin plate onto the metal plate. As the methodfor bonding the metal plate and the resin plate, various tackinessagents may be used, or a resin plate having self-adhesiveness may beused, for example. Note that it is known that a resin causes change withpassage of time for a certain time period after molding, and therefore,a so-called aging time period needs to be provided until the shape isfixed. Since it is conceivable that in the commercially available metalplate 60 with a resin layer, a so-called aging time period has elapsed,use of a commercially available metal plate with a resin layer ispreferable from the viewpoint of yield.

Next, slits that penetrate through only the metal plate are formed for ametal plate 61 in the aforementioned metal plate 60 with a resin layer,and thereby a metal mask 68 with a resin layer is formed. The processstep in the present method is not specially limited, and may be anyprocess step as long as desired slits can be formed in only the metalmask. The metal mask 68 with a resin layer mentioned in the descriptionof the present application means the metal mask with a resin layer inwhich slits are formed in the metal plate of the above described metalplate 60 with a resin layer.

FIGS. 1 (b) to (d) show an example of the process of forming the metalmask 68 with a resin layer. As shown in FIG. 1 (b), a surface where aresin layer 67 is not provided, of the aforementioned metal plate 60with a resin layer, is coated with a resist material 62, and the resistmaterial is masked with use of a mask 63 in which a slit pattern isformed, and is exposed and developed. Thereby, as shown in FIG. 1 (c), aresist pattern 64 is formed on a front surface of the metal plate 67.Subsequently, with use of the resist pattern 64 as an etching resistantmask, only the metal plate 60 is subjected to etching processing, andafter etching is finished, the aforementioned resist pattern is cleanedand removed. Thereby, as shown in FIG. 1 (d), a metal mask 66 (the metalmask 68 with a resin layer) in which slits 65 are formed in only themetal plate 67 can be obtained.

A method for masking the resist material is not specially limited, andonly the surface side of the metal plate 60 with a resin layer where theresin layer 67 is not provided may be coated with the resist material62, or both surfaces of the metal plate 60 with a resin layer may becoated with the resist material 62 (not illustrated). Further, a dryfilm method that bonds dry film resist onto the surface of the metalplate 60 with a resin layer, where the resin layer 67 is not provided,or both the surfaces of the metal plate 60 with a resin layer also canbe used. The method for coating the resist material 62 is not speciallylimited, and when only the surface side where the resin layer 67 is notprovided, of the metal plate 60 with a resin layer is coated with theresist material 62, a spin coat method, and a spray coat method can beused. Meanwhile, in the case of using the metal plate 60 with a resinlayer in a long sheet shape, a dip coat method or the like that can coata resist material by a roll-to-roll method is preferably used. Note thatwith a dip coat method, both the surfaces of the metal plate 60 with aresin layer are coated with the resist material 62.

Note that as the resist material, a resist material with excellenttreatability and with desired resolution is preferably used. Further,the etching agent for use at the time of etching, processing is notspecially limited, and a known etching agent can be properly selected.

A method for etching the metal plate 60 is not specially limited, andfor example, a wet etching method such as a spray etching method thatsprays an etching agent at a predetermined spray pressure from aninjection nozzle, an immersion etching method that immerses the metalplate 60 into an etching solution filled with an etching agent, and aspin etching method that drops an etching agent, and a dry etchingmethod using gas, plasma or the like can be used.

Next, a laser is emitted through the slits 65 from the metal mask 66side of the metal plate 68 with a resin layer, and openings 69corresponding to a pattern to be produced by vapor deposition are formedin a plurality of rows lengthwise and crosswise in the resin layer 67,whereby a resin mask 70 is made. A laser apparatus that is used here isnot specially limited, and a conventionally known laser apparatus may beused. Thereby, a vapor deposition mask 80 as shown in FIG. 1 (e) isobtained. Note that the pattern to be produced by vapor deposition inthe description of the present application means a pattern to beproduced with use of the vapor deposition mask, and for example, in thecase of use of the vapor deposition mask in formation of an organiclayer of an organic EL element, the pattern is in a shape of the organiclayer. The same shall apply to production methods of other embodimentshereinafter.

Second Production Method

FIGS. 2 (a)-(e) are a process chart for describing a second productionmethod of the vapor deposition mask of the present invention. Note thatFIGS. 2 (a) to (e) are all sectional views.

In the first production method shown in FIGS. 1 (a)-(e), a resistpattern 64 that is used as the etching mask at the time of forming themetal mask 66 is removed, but the resist pattern 64 may be allowed toremain without being removed as shown in FIG. 2 (d) and FIG. 2 (e). Theother process steps, namely, FIGS. 2 (a) to (c) are similar to theprocess steps in FIGS. 1 (a) to (e), and therefore, explanation will beomitted here.

Note that in the above described first and second production methods,the metal mask 68 with a resin layer may be fixed to a frame containinga metal, after the metal mask 66 (the metal mask 68 with a resin layer)is formed, namely, between (d) and (e) of FIGS. 1 (a)-(e) and FIGS. 2(a)-(e). By fixing the metal mask with a resin layer to a frame at astage before the openings 69 of the resin mask 70 that controls thepattern shape that is finally produced by vapor deposition are formed, amounting error that occurs when the vapor deposition mask is fixed tothe frame can be made zero. Note that in a conventionally known method,the metal mask in which openings are determined is fixed to the framewhile being pulled, and therefore, precision of position coordinates ofthe openings is reduced.

Further, when the openings 69 are provided in the resin layer of themetal mask 68 with a resin layer in a state fixed to a frame accordingto a laser processing method, a reference sheet provided in advance witha pattern to be produced by vapor deposition, namely, a patterncorresponding to the openings 69 to be formed is prepared, and laserirradiation corresponding to the pattern on the reference sheet may beperformed from the metal mask 66 side, in a state in which the referencesheet is bonded to the surface where the metal mask 66 is not provided,of the metal mask 68 with a resin layer. According to the method, theopenings 69 can be formed in the resin layer 67 in a so-calledface-to-face state in which laser irradiation is performed while thepattern on the reference sheet bonded to the metal mask 68 with a resinlayer is being watched, and the resin mask 70 having the openings 69with high definition in which the dimensional precision of the openingsis extremely high can be formed. Further, in this method, formation ofthe openings 69 is performed in the state fixed to the frame, andtherefore, the vapor deposition mask that is excellent in not onlydimensional precision but also in positional precision can be made.

Note that when the above described method is used, the pattern on thereference sheet needs to be recognizable with a laser irradiationapparatus through the resin layer 67 from the metal mask 66 side. As theresin layer 67, use of a resin layer having transparency is needed whenthe resin layer has a certain degree of thickness, but when the resinlayer has a preferable thickness with consideration given to aninfluence on a shadow as will be described later, for example, athickness of about 3 μm to 25 μm, the pattern on the reference sheet canbe recognized even if the resin layer is a colored resin layer.

A method for bonding the resin layer and the reference sheet is notspecially limited. For example, when the metal mask 66 is of a magneticsubstance, a magnet or the like is arranged at a rear side of thereference sheet, and the resin layer 67 and the reference sheet can bebonded to each other by being attracted. Besides this, the resin layer67 and the reference sheet can be bonded with use of an electrostaticadsorbing method or the like. As the reference sheet, a TFT substratehaving a predetermined pattern, a photo mask and the like can be cited,for example.

According to each of the first and second production methods of thepresent invention as above, the vapor deposition mask that can satisfyboth enhancement in definition and reduction in weight can be producedwith high yield even when the size is increased. Further, according toone embodiment of the present invention, the positional precision of theframe and the vapor deposition mask 100 can be enhanced. Further, byforming the opening 69 with use of the reference sheet, the opening 69that is extremely excellent in positional precision can be made.

More specifically, in the production method of the present invention,the vapor deposition mask 100 in which the resin mask 70 and the metalmask 66 are stacked is produced. Here, when a mass of the vapordeposition mask 100 that is produced according to the production methodof the present invention, and a mass of the vapor deposition mask thatis composed of only a metal and is conventionally known are compared onthe assumption that thicknesses of the entire vapor deposition masks arethe same, the mass of the vapor deposition mask 100 of the presentinvention is lighter by an amount of a part of the metal material of theconventionally known vapor deposition mask, which is replaced with aresin material. Further, in order to reduce weight by using the vapordeposition mask composed of only a metal, it is necessary to reduce thethickness of the vapor deposition mask, but when the thickness of thevapor deposition mask is reduced, distortion sometimes occurs to thevapor deposition mask, and reduction in durability sometimes occurs whenupsizing the vapor deposition mask. Meanwhile, according to the vapordeposition mask according to the present invention, even when thethickness of the entire vapor deposition mask is increased to satisfydistortion and durability at the time of the mask being upsized,reduction in weight can be achieved more than the vapor deposition maskthat is formed of only a metal by the presence of the resin mask 70.

Further, in the production method of the present invention, the resinmask 70 is obtained by irradiating the resin layer 67, in whichformation of the openings with higher definition is enabled as comparedwith a metal material, with a laser, and therefore, the vapor depositionmask 100 having the openings 69 with high definition can be produced.

Slimming Step

Further, in the production method of the present invention, a slimmingstep may be performed between the steps described above, or after thesteps. The step is an optional step in the production method of thepresent invention, and is the step of optimizing the thickness of themetal mask 66, and the thickness of the resin mask 70. The preferablethicknesses of the metal mask 66 and the resin mask 70 may be properlyset in preferable ranges that will be described later, and the detailedexplanation will be omitted here.

For example, when as the metal plate 60 with a resin layer, a metalplate with a resin layer having a certain degree of thickness is used,excellent durability and transportability can be given when the metalplate 60 with a resin layer and the metal mask 68 with a resin layer aretransported, and when the vapor deposition mask 100 that is producedaccording to the above described production method is transported,during the production process. Meanwhile, in order to prevent generationof a shadow or the like, the thickness of the vapor deposition mask 100that is obtained according to the production method of the presentinvention is preferably an optimum thickness. The slimming step is auseful step in the case of optimizing the thickness of the vapordeposition mask 100 while satisfying durability and transportabilityduring the production process or after the process.

Slimming of the metal plate 61 to be the metal mask 66 and the metalmask 66, namely, optimization of the thickness of the metal mask can berealized by etching the surface at the side that is not in contact withthe resin layer 67, of the metal plate 61, or the surface at the sidethat is not in contact with the resin layer 67 or the resin mask 70, ofthe metal mask 66 by using the etching agent capable of etching themetal plate 61 and the metal mask 66, between the steps described above,or after the steps.

Slimming of the resin layer 67 to be the resin mask 70 and the resinmask 70, namely, optimization of the thicknesses of the resin layer 67and the resin mask 70 is similar to the above, and can be realized byetching the surface at the side that is not in contact with the metalplate 61 and the metal mask 66, of the resin layer 70, or the surface atthe side that is not in contact with the metal mask 66, of the resinmask 70 by using the etching agent capable of etching the materials ofthe resin layer 67 and the resin mask 70 between any of the stepsdescribed above, or after the steps. Further, after the vapor depositionmask 100 is formed, both the metal mask 66 and the resin mask 70 aresubjected to etching processing, whereby the thicknesses of both of themalso can be optimized.

In the slimming step, the etching agent for etching the resin layer 67or the resin mask 70 can be properly set in accordance with the resinmaterial of the resin layer 67 or the resin mask 70, and is notspecially limited. For example, when a polyimide resin is used as theresin material for the resin layer 67 or the resin mask 70, an alkaliaqueous solution in which sodium hydroxide or potassium hydroxide isdissolved, hydrazine and the like can be used, as the etching agent. Asthe etching agent, a commercially available product also can be directlyused, and as the etching agent for a polyimide resin, TPE3000 made byToray Engineering Co., Ltd. or the like is usable.

Vapor Deposition Mask Produced According to First Production Method

FIG. 3 (a) is a front view of the vapor deposition mask producedaccording to the aforementioned first production method, seen from themetal mask side, and FIG. 3 (b) is an enlarged sectional view of thevapor deposition mask 100 produced according to the aforementioned firstproduction method. Note that in these drawings, in order to emphasizethe slits provided in the metal mask and the openings provided in thevapor deposition mask, the ratios thereof to the entire body areillustrated to be large. Note that for convenience of explanation, inthe forms shown in FIGS. 3 (a)-(b) to FIGS. 6 (a)-(c), the metal mask isdesignated by reference sign 10, and the resin mask is designated byreference sign 20, and the metal mask 10 can be directly replaced withthe metal mask 66 described in the production method of the abovedescribed present invention, whereas the resin mask 20 can be directlyreplaced with the metal mask 70 described in the production method ofthe above described present invention.

As shown in FIG. 3 (a), the vapor deposition mask 100 that is producedaccording to the first production method of the present invention adoptsa configuration in which the metal mask 10 provided with the slits 15,and the resin mask 20 that is positioned on a front surface of the metalmask 10 (an undersurface of the metal mask 10 in the case shown in FIG.3 (b)), and has the openings 25 corresponding to the pattern to beproduced by vapor deposition arranged by lengthwise and crosswise in aplurality of rows are stacked. Hereinafter, respective members will bedescribed specifically.

Resin Mask

The resin mask 20 is composed of a resin, and as shown in FIG. 3 (b),the openings 25 corresponding to a pattern to be produced by vapordeposition are arranged by lengthwise and crosswise in a plurality ofrows at the positions overlapping the slit 15. Further, while in thepresent invention, the example in which the openings are arranged bylengthwise and crosswise in a plurality of rows is cited and described,the openings 25 can be provided in the positions overlapping the slits,and when the slits are arranged in only a single row in the lengthwisedirection or the crosswise direction, the openings 25 can be provided atthe positions overlapping the slit 15 in the single row.

For the resin mask 20, a conventionally known resin material can beproperly selected and used, and while the material is not especiallylimited, a material that enables formation of the opening 25 with highdefinition by laser processing or the like, has a low rate ofdimensional change and a low rate of humidity absorption under heat andwith passage of time, and is lightweight, is preferably used. As suchmaterials, a polyimide resin, a polyamide resin, a polyamide-imideresin, a polyester resin, a polyethylene resin, a polyvinylalcoholresin, a polypropylene resin, a polycarbonate resin, a polystyreneresin, a polyacrylonitrile resin, an ethylene-vinyl acetate copolymerresin, an ethylene-vinyl alcohol copolymer resin, anethylene-methacrylic acid copolymer resin, a polyvinyl chloride resin, apolyvinylidene chloride resin, cellophane, an ionomer resin and the likecan be cited. Among the materials illustrated in the above, the resinmaterials with the thermal expansion coefficients of 16 ppm/° C. or lessare preferable, the resin materials with rates of humidity absorption of1.0% or less are preferable, and the resin materials including both theconditions are especially preferable. Accordingly, the resin layers 67in FIGS. 1 (a)-(e) and FIGS. 2 (a)-(e) become the resin masks 20 in thefuture, and therefore, the resin layers composed of, for example, thepreferable resin materials illustrated in the above are preferably used.

While the thickness of the resin mask 20 is not especially limited, theresin mask 20 is preferably as thin as possible in order to preventoccurrence of an insufficient vapor deposition portion, namely, a vapordeposition portion with a film thickness smaller than the intended vapordeposition film thickness, a so-called shadow, in the pattern that isproduced by vapor deposition, when vapor deposition is performed withuse of the vapor deposition mask of the present invention. However, whenthe thickness of the resin mask 20 is less than 3 μm, a defect such as apinhole easily occurs, and the risk of deformation or the likeincreases. Meanwhile, when the thickness of the resin mask 20 exceeds 25μm, generation of a shadow can arise. With this point taken intoconsideration, the thickness of the resin mask 20 is preferably from 3μm to 25μ inclusive. By setting the thickness of the resin mask 20within this range, the defect such as a pinhole and the risk ofdeformation or the like can be reduced, and generation of a shadow canbe effectively prevented. In particular, the thickness of the resin mask20 is set to be from 3 μm to 10 μm inclusive, more preferably, from 4 μmto 8 μm inclusive, whereby the influence of a shadow at the time offorming a high-definition pattern exceeding 300 ppi can be preventedmore effectively. Accordingly, the resin layers 67 in FIGS. 1 (a)-(e)and FIGS. 2 (a)-(e) become the resin masks 20 in the future, andtherefore, the thicknesses of the resin layers 67 are preferably set atthe thicknesses described above. Note that the resin layer 67 may bejoined to the metal plate via a tackiness agent layer or an adhesiveagent layer, or the resin layer 67 and the metal plate may be directlyjoined to each other, but when the resin layer and the metal plate arejoined to each other via a tackiness agent layer or an adhesive agentlayer, the total thickness of the resin layer 67 and the tackiness agentlayer, or the resin layer 67 and the adhesive agent layer is preferablyset to be within a range from 3 μm to 25 μm inclusive in considerationof the shadow described above.

The shape and the size of the opening 25 are not especially limited, andcan be the shape and the size corresponding to the pattern to beproduced by vapor deposition. Further, as shown in FIG. 2 (a), a pitchP1 in a crosswise direction of the adjacent openings 25, and a pitch P2in a lengthwise direction can be also properly set in accordance withthe pattern to be produced by vapor deposition. Accordingly, when theopenings are formed by laser irradiation in FIGS. 1 (a)-(e) and FIGS. 2(a)-(e), the above described pitches P1 and P2 may be properly designed.

The positions at which the openings 25 are provided and the number ofthe openings 25 are not specially limited, and a single opening 25 maybe provided at a position overlapping the slit 15, or a plurality ofopenings 25 may be provided in the lengthwise direction, or thecrosswise direction. For example, as shown in FIG. 5 (a), when the slitextends in the lengthwise direction, two or more of the openings 25 thatoverlap the slit 15 may be provided in the crosswise direction.

A sectional shape of the opening 25 is not specially limited, and endsurfaces that face each other of the resin mask forming the opening 25may be substantially parallel with each other, but the sectional shapeof the opening 25 is preferably is the shape having broadening toward avapor deposition source. In other words, the sectional shape of theopening 25 preferably has a taper surface having broadening toward themetal mask 10 side. By making the sectional shape of the opening 25 havethe above configuration, a shadow can be prevented from being generatedin the pattern that is produced by vapor deposition when vapordeposition is performed with use of the vapor deposition mask of thepresent invention. While a taper angle θ can be properly set with thethickness or the like of the resin mask 20 taken into consideration, anangle connecting a lower bottom distal end in the opening of the resinmask and an upper bottom distal end in the opening of the same resinmask is preferably within a range from 25° to 65°. In particular, withinthis range, the angle (θ) is preferably an angle smaller than a vapordeposition angle of a vapor deposition machine to be used. Furthermore,in FIG. 3 (b) and FIG. 4, an end surface 25 a that forms the opening 25shows a linear shape, but the end surface 25 a is not limited thereto,and may be in a curved shape protruding outward, namely, a shape of theentire opening 25 may be in a bowl shape. The opening 25 that has thesectional shape like this can be formed by performing multistage laserirradiation that properly adjusts the irradiation position of the laserand irradiation energy of the laser at the time of formation of theopening 25, or changes the irradiation position stepwise.

Further, in the present invention, as the configuration of the vapordeposition mask 100, the resin mask 20 is used. Therefore, when vapordeposition is performed with use of the vapor deposition mask 100, veryhigh heat is applied to the openings 25 of the resin mask 20, and therisk of a gas being generated from end surfaces 25 a (see FIG. 3 (b))that form the opening 25 of the resin mask 20 to reduce the degree ofvacuum in the vapor deposition apparatus or the like can arise.Accordingly, with this point taken into consideration, the end surfaces25 a that form the opening 25 of the resin mask 20 are preferablyprovided with a barrier layer 26 as shown in FIG. 3 (b). By forming thebarrier layer 26, a gas can be prevented from being generated from theend surfaces 25 a that form the opening 25 of the resin mask 20.

As the barrier layer 26, a thin film layer or a vapor deposition layerof an inorganic oxide, an inorganic nitride or a metal can be used. Asan inorganic oxide, oxides of aluminum, silicon, indium, tin andmagnesium can be used, and as a metal, aluminum or the like can be used.A thickness of the barrier layer 26 is preferably about 0.05 μm to 1 μm.Accordingly, in the production methods of the present inventiondescribed in FIGS. 1 (a)-(e) and FIGS. 2 (a)-(e), a step of forming thebarrier layer 26 as described above may be performed after the vapordeposition mask 80 is obtained.

Furthermore, the barrier layer preferably covers a front surface at thevapor deposition source side, of the resin mask 20. The front surface atthe vapor deposition source side, of the resin mask 20 is covered withthe barrier layer 26, whereby a barrier property thereof is furtherenhanced. The barrier layer is preferably formed by various PVD methodsand CVD methods in the case of an inorganic oxide and an inorganicnitride. In the case of a metal, the barrier layer is preferably formedby a vacuum vapor deposition method. Note that the front surface at thevapor deposition source side, of the resin mask 20 mentioned here may bethe entire front surface at the vapor deposition source side, of theresin mask 20, or may be only portions exposed from the metal mask inthe front surface at the vapor deposition source side, of the resin mask20.

Metal Mask

The metal mask 10 is composed of a metal, and the slits 15 that extendin the lengthwise direction or the crosswise direction are arranged in aplurality of rows in the position overlapping the openings 25, in otherwords, in the position where all of the openings 25 arranged in theresin mask 20 are visible, when seen from a front of the metal mask 10.Note that in FIG. 3 (a), the slits 15 that extend in the lengthwisedirection of the metal mask 10 are continuously arranged in thecrosswise direction. Further, in the present invention, the example inwhich the slits 15 that extend in the lengthwise direction or thecrosswise direction are arranged in a plurality of rows is cited anddescribed, but the slits 15 may be arranged in only a single row in thelengthwise direction or in the crosswise direction.

While a width W of the slit 15 is not specially limited, the width W ispreferably designed to be shorter than at least the pitch between theadjacent openings 25. More specifically, as shown in FIG. 2 (a), whenthe slit 15 extends in the lengthwise direction, the width W in thecrosswise direction of the slit 15 is preferably made shorter than thepitch P1 of the openings 25 adjacent to each other in the crosswisedirection. Similarly, though not illustrated, when the slit 15 extendsin the crosswise direction, a width in the lengthwise direction of theslit 15 is preferably made shorter than a pitch P2 of the openings 25adjacent to each other in the lengthwise direction. Meanwhile, a lengthL in the lengthwise direction in a case of the slit 15 extending in thelengthwise direction is not specially limited, and can be properlydesigned in accordance with the lengthwise length of the metal mask 10and the positions of the openings 25 that are provided in the resin mask20. Accordingly, in the production methods of the present inventiondescribed in FIGS. 1 (a)-(e) and FIGS. 2 (a)-(e), the metal plate isdesigned as described above when the metal plate is etched.

Further, the slit 15 that continuously extends in the lengthwisedirection, or in the crosswise direction may be divided into a pluralityof portions by a bridge 18 as shown in FIG. 5 (b). Note that FIG. 5 (b)is a front view of the vapor deposition mask 100 seen from the metalmask 10 side, and shows an example in which the single slit 15continuously extending in the lengthwise direction shown in FIG. 3 (a)are divided into a plurality of portions (slits 15 a and 15 b) by thebridge 18. While a width of the bridge 18 is not specially limited, thewidth of the bridge 18 is preferably around 5 μm to 20 μm. By settingthe width of the bridge 18 to be within this range, the rigidity of themetal mask 10 can be effectively enhanced. The arrangement position ofthe bridge 18 is not specially limited, but the bridge 18 is preferablyarranged in such a manner that the slit after being divided is overlaidon the two or more of the openings 25.

While a sectional shape of the slit 15 that is formed in the metal mask10 is not specially limited, either, the sectional shape is preferably ashape that has broadening toward the vapor deposition source as shown inFIG. 3 (b), similarly to the opening 25 in the above described resinmask 20. Accordingly, in the production methods of the present inventiondescribed in FIGS. 1 (a)-(e) and FIGS. 2 (a)-(e), etching is preferablyperformed so that the sectional shape as described above is obtainedwhen the metal plate is etched.

The material of the metal mask 10 is not specially limited, and theconventionally known material in the field of the vapor deposition maskcan be properly selected and used, and, for example, a metal materialsuch as stainless steel, an iron-nickel alloy, and an aluminum alloy canbe cited. Above all, an invar material that is an iron-nickel alloy canbe preferably used since an invar material is hardly deformed by heat.

Further, when the vapor deposition mask 100 at a front side of thesubstrate needs to be attracted by a magnetic force by arranging amagnet or the like at a rear side of the substrate when vapor depositionis performed onto the substrate with use of the vapor deposition mask100 of the present invention, the metal mask 10 is preferably formed ofa magnetic substance. As the metal mask 10 of a magnetic substance, pureiron, carbon steel, W steel, Cr steel, Co steel, KS steel, MK steel, NKSsteel, Cunico steel, an AL-Fe alloy and the like can be cited. Further,when the material itself that forms the metal mask 10 is not of amagnetic substance, magnetism may be given to the metal mask 10 bydispersing powder of the above described magnetic substance into thematerial.

While the thickness of the metal mask 10 is not specially limited, thethickness is preferably around 5 μm to 100 μm. In the case ofconsideration being given to prevention of a shadow at the time of vapordeposition, the thickness of the metal mask 10 is preferably small, butwhen the thickness of the metal mask 10 is made thinner than 5 μm, therisk of breakage and deformation is increased, and handling is likely tobe difficult. However, since in the present invention, the metal mask 10is integrated with the resin mask 20, the risks of breakage anddeformation can be reduced even if the thickness of the metal mask 10 isvery small such as 5 μm, and a metal mask is usable if the thicknessthereof is 5 μm or more. Note that the case in which the thickness ofthe metal mask 10 is made larger than 100 μm is not preferable becausegeneration of a shadow can arise. Accordingly, in the production methodsof the present invention described in FIGS. 1 (a)-(e) and FIGS. 2(a)-(e) 2, when the metal plate with a resin layer is prepared, themetal plate with a resin layer is preferably prepared with thosedescribed above taken into consideration.

Hereinafter, with use of FIG. 6 (a) to FIG. 6 (c), a relation ofgeneration of a shadow, and the thickness of the metal mask 10 will bespecifically described. As shown in FIG. 6 (a), when the thickness ofthe metal mask 10 is small, the vapor deposition material that isreleased toward a vapor deposition target from a vapor deposition sourcepasses through the slit 15 of the metal mask 10 and the opening 25 ofthe resin mask 20 without colliding with an inner wall surface of theslit 15 of the metal mask 10 and a surface of the metal mask 10 at aside where the resin mask 20 is not provided, and reaches the vapordeposition target. Thereby, formation of the vapor deposition patternwith a uniform film thickness onto the vapor deposition target isenabled. Namely, generation of a shadow can be prevented. Meanwhile, asshown in FIG. 6 (b), when the thickness of the metal mask 10 is large,for example, when the thickness of the metal mask 10 is a thicknessexceeding 100 μm, a part of the vapor deposition material that isreleased from the vapor deposition source collides with the inner wallsurfaces of the slit 15 of the metal mask 10, and the surface of themetal mask 10 at the side where the resin mask 20 is not formed, andcannot reach the vapor deposition target. As the vapor depositionmaterial that cannot reach the vapor deposition target increases more,an undeposited portion having a film thickness smaller than the intendedvapor deposition film thickness occurs to the vapor deposition targetmore, namely, a shadow is generated.

In order to prevent generation of a shadow sufficiently, the sectionalshape of the slit 15 is preferably made a shape having broadening towardthe vapor deposition source, as shown in FIG. 6 (c). By adopting thesectional shape like this, the vapor deposition material can be causedto reach the vapor deposition target without the vapor depositionmaterial that is released from the vapor deposition source collidingwith the surface of the slit 15 and the inner wall surface of the slit15 even if the thickness of the entire vapor deposition mask is madelarge with the objective of prevention of distortion that can occur tothe vapor deposition mask 100, or enhancement of durability. Morespecifically, the angle that is formed by a straight line connecting thelower bottom distal end in the slit 15 of the metal mask 10 and theupper bottom distal end in the slit 15 of the same metal mask 10, andthe bottom surface of the metal mask 10 is preferably within a range of25° to 65°. In particular, in this range, an angle that is smaller thanthe vapor deposition angle of the vapor deposition machine to be used ispreferable. By adopting the sectional shape like this, the depositionmaterial can be caused to reach the vapor deposition target without thevapor deposition material released from the vapor deposition sourcecolliding with the inner wall surface of the slit 15 even when thethickness of the metal mask 10 is made relatively large with theobjective of prevention of distortion that can arise in the vapordeposition mask 100, or enhancement of durability. Thereby, generationof a shadow can be prevented more effectively. Note that FIGS. 6 (a)-(c)are partial schematic sectional views for explaining the relation ofgeneration of a shadow and the slit 15 of the metal mask 10. Note thatin the form shown in FIG. 6 (c), the slit 15 of the metal mask 10 hasthe shape having broadening toward the vapor deposition source side, andthe end surfaces that face each other of the opening of the resin mask20 are substantially parallel with each other, but in order to preventgeneration of a shadow more effectively, the sectional shapes of boththe slit of the metal mask 10 and the opening 25 of the resin mask 20are preferably the shapes having broadening toward the vapor depositionsource side. Accordingly, in the method for producing the vapordeposition mask of the present invention, the slit 15 of the metal mask10 and the opening 25 of the resin mask 20 are preferably produced sothat the sectional shapes of the slit of the metal mask and the openingof the resin mask become the shapes having broadening toward the vapordeposition source side.

FIGS. 7 (a) to (d) are partial schematic sectional views showing therelation of the slit of the metal mask and the opening of the resinmask, and in the forms that are illustrated, the sectional shapes ofentire openings that are formed by the slits 15 of the metal masks andthe openings 25 of the resin masks show step shapes. As shown in FIGS. 7(a)-(d), the sectional shapes of the entire openings are formed intostep shapes having broadening toward the vapor deposition source sides,whereby generation of a shadow can be prevented effectively.

Accordingly, in the method for producing the vapor deposition mask ofthe present invention, the vapor deposition mask is preferably producedin such a manner that the sectional shape of the entire opening that isformed by the slit of the metal mask and the opening 25 of the resinmask becomes a step shape.

In the sectional shapes of the slit 15 of the metal mask and the resinmask 20, the end surfaces that face each other may be substantiallyparallel with each other as shown in FIG. 7 (a), but as shown in FIGS. 7(b) and (c), only any one of the slit 15 of the metal mask and theopening of the resin mask may have a sectional shape having broadeningtoward the vapor deposition source side. Note that as described in theabove, in order to prevent generation of a shadow more effectively, bothof the slit 15 of the metal mask, and the opening 25 of the resin maskpreferably have the sectional shapes having broadening toward the vapordeposition source side as shown in FIG. 3 (b) and FIG. 7 (d).

A width of a flat portion (reference sign (X) in FIGS. 7 (a)-(d)) in thesection formed into the above described step shape is not speciallylimited, but when the width of the flat portion (X) is less than 1 μm,the effect of prevention of shadow generation tends to reduce due tointerference of the slit of the metal mask. Accordingly, with this pointtaken into consideration, the width of the flat portion (X) ispreferably 1 μm or more. A preferable upper limit value is not speciallylimited, and can be properly set with consideration given to the size ofthe opening of the resin mask, the space between the adjacent openingsand the like, and as one example, the preferable upper limit value isapproximately 20 μm.

Note that FIGS. 7 (a) to (d) described above each shows an example inwhich the single opening 25 that overlaps the slit 15 is provided in thecrosswise direction when the slit extends in the lengthwise direction,but as shown in FIG. 8, two or more of the openings 25 that overlap theslit 15 may be provided in the crosswise direction when the slit extendsin the lengthwise direction. In FIG. 8, both the slit 15 of the metalmask and the opening 25 of the resin mask have sectional shapes havingbroadening toward the vapor deposition source side, and two or more ofthe openings 25 that overlap the slit 15 are provided in the crosswisedirection.

Vapor Deposition Mask Produced According to Second Production Method

FIG. 4 is an enlarged sectional view of the vapor deposition mask thatis produced according to the second production method.

As shown in FIG. 4, the vapor deposition mask 100 produced by the secondproduction method differs from the vapor deposition mask produced by thefirst production method shown in FIGS. 1 (a)-(e) in only the point thata resist pattern 30 remains in the vapor deposition mask 100 produced bythe second production method, and is the same as the vapor depositionmask produced by the first production method in the other points.Accordingly, explanation of the metal mask 10 and the resin mask 20 willbe omitted.

Resist Pattern

The resist pattern 30 is a resist pattern that is used as an etchingmask when the metal plate is etched, and is composed of a resistmaterial. The pattern is substantially the same as the slits formed inthe metal mask 10. Note that the sectional shape of an opening 31 of theresist pattern 30 is preferably made a shape having broadening towardthe vapor deposition source as shown in FIG. 4.

Since in the vapor deposition mask that is produced by the secondproduction method like this, both the surfaces of the metal mask arecovered with a resin, expansion uniformly occurs in both the surfacesthereof even when the resin is expanded by heat at the time of vapordeposition, and therefore, curl hardly occurs as compared with the casein which a resin is present on only one surface, which is preferable. Inorder to exhibit the effect efficiently, the materials of both of theresin layer provided on the metal plate and the resist material arepreferably selected so that the difference between the thermalcoefficients of the material of the resin composing the resin mask, thatis the resin layer provided on the metal plate and the material of theresist material composing the resist pattern becomes small.

Method for Producing Organic Semiconductor Element

A method for producing an organic semiconductor element of the presentinvention is characterized by forming an organic semiconductor elementby using the vapor deposition mask 100 produced according to theproduction method of the present invention described in the above. Asfor the vapor deposition mask 100, the vapor deposition mask 100produced according to the production method of the present inventiondescribed above can be directly used, and therefore, the detailedexplanation here will be omitted. According to the vapor deposition maskof the present invention described above, an organic semiconductorelement having a pattern with high definition can be formed by theopenings 25 with high dimensional precision which are included by thevapor deposition mask 100. As the organic semiconductor element that isproduced according to the production method of the present invention, anorganic layer of an organic EL element, a light emitting layer, acathode electrode and the like, for example, can be cited. Inparticular, the method for producing the organic semiconductor elementof the present invention can be favorably used in production of the R, Gand B light emitting layers of the organic EL element which are requiredto have pattern precision with high definition.

REFERENCE SIGNS LIST

-   100 Vapor deposition mask-   10, 66 Metal mask-   15 Slit-   18 Bridge-   20, 70 Resin mask-   25 Opening-   60 Metal plate with resin layer-   61 Metal plate-   62 Resist material-   64 Resist pattern-   67 Resin layer-   68 Metal plate with resin layer-   80 Vapor deposition mask

1. A method for producing a vapor deposition mask that is formed by ametal mask provided with a slit, and a polyimide resin mask that isstacked on a front surface of the metal mask, and has openingscorresponding to a pattern to be produced by vapor deposition,comprising the steps of: providing a metal plate with a polyimide resinlayer formed on one surface of the metal plate; forming the metal maskwith the polyimide resin layer by forming a slit that penetrates throughonly the metal plate; and forming the polyimide resin mask by formingthe openings corresponding to a pattern to be produced by vapordeposition in the polyimide resin layer by emitting a laser from themetal mask side.